I do have a syslog server. A working session generates logs such as:
<134>1 2019-07-26T12:06:20+08:00 DC101VCMP02 info - - - tmm[18608]: Rule /Common/Log_Verbose_Connections <HTTP_REQUEST>: HTTP request received to VIP: 10.70.221.46:443 with URL: quality.mysite.net.au/pay-my-bill.html?p=5192536012
<134>1 2019-07-26T12:06:20+08:00 DC101VCMP02 info - - - tmm[18608]: Rule /Common/Log_Verbose_Connections <SERVER_CONNECTED>: connected client: 1.127.104.74:59579 to node: 172.21.251.42:818
1
<134>1 2019-07-26T12:06:20+08:00 DC101VCMP02 info - - - tmm[18608]: Rule /Common/Log_Verbose_Connections <HTTP_RESPONSE>: HTTP response - Client: 1.127.104.74:59579 -> VIP:10.70.221.46:443
URL:quality.mysite.net.au/pay-my-bill.html?p=5192536012 -> Node: 172.21.251.42:8181 with response 200
The problem traffic shows up in the log as:
<134>1 2019-07-26T11:41:44+08:00 DC101VCMP02 info - - - tmm[18608]: Rule /Common/Log_Verbose_Connections <HTTP_REQUEST>: HTTP request received to VIP: 10.70.221.46:443 with URL: quality.mysite.net.au/apps/rest/payment/GetDueBalanceDetails_PaymentNumber
<134>1 2019-07-26T11:42:19+08:00 DC101VCMP02 info - - - tmm[18608]: Rule /Common/Log_Verbose_Connections <HTTP_REQUEST>: HTTP request received to VIP: 10.70.221.46:443 with URL: quality.mysite.net.au/apps/rest/payment/GetDueBalanceDetails_PaymentNumber
There are no corresponding SERVER_CONNECTED or HTTP_RESPONSE entries. A tcpdump does not show the request egressing the F5